Fluid fuel burning apparatus



Jan. 20, 1959 R. M. SHERMAN 2,859,626

' FLUID FUEL BURNING APPARATUS Filed June 28, 1954 3 Sheets-Sheet l INVENTOR RALLSTO/V M.

ll //ooooooooo ooooooco ODD OOOOOOOOu 0 SHERMAN BVMEMW W N I Jan. 20, 1959 R. M. SHERMAN FLUID FUEL BURNING APPARATUS 3 Sheets-Sheet 2 Filed June 28, 1954 000000 -OOoo0oOO DQ000130s QOOOOOOC INVENTOR .SZERMA/V w MATTKS.

FALLS TON M fiaum/ Jan. 20, 1959 R. M. SHERMAN 2,869,625

FLUID FUEL BURNING APPARATUS Filed June 28. 1954 I V 3 Sheets-Sheet 3 FIG] ' 0 000 00 000000 0090000 0000 o l w a fig g RALLS TON M. SHERMAN BY United States Patent FLUID FUEL BURNING APPARATUS Rallston M. Sherman, Glastonbury, Conn., assignor to ,The Silent Glow Gil Burner Corporation, Hartford,

Conn., a corporation of Connecticut Application June 28, 1954, Serial No. 439,653

Claims. (Cl. 158-4) My invention relates to fluid fuel burning apparatus, and constitutes an improvement in the apparatus forming the subject of applicants United States Patent 2,669,297, dated February 16, 1954.

The present invention has among its objects the provision of a perforated drum-like combustion chamber, of the type disclosed by said patent, by use of which hotter combustion products'can be obtained for the same amount of fuel burned therein than by use of the combustion chamber according to said patent. The invention and its other objects, however, will be best understood from the following description when read in the light of the accompanying drawings of several forms of apparatus according'to the invention, while the scope of the invention will be more particularly pointed out in the appended claims.

In the drawings:

Fig. l is a longitudinal medial vertical section, with parts in elevation, of an oil burning apparatus according to the invention;

Fig. 2 shows a detail of a modified form of the combustion chamber according to Fig. 1, corresponding to an end elevation on a reduced scale of the combustion chamber according to Fig. 1 as viewed from the right;

Fig. 3 is a fragment of a longitudinal medial vertical section of a modified form of the combustion chamber;

Fig. 4 is a fragment of a longitudinal medial vertical section of a further modified 'form of'the combustion chamber;

Figs. 5, 6, 7 and 8 are, respectively, longitudinal medial vertical sections of still further modified forms of combustion chamber according to the invention; and

Fig. 9 is a fragment of a development of the lateral wall of another modified form of combustion chamber according to the invention.

Referring particularly to Fig. 1 of the drawings, the combustion chamber shown is in the form of a sheet metal drum having a cylindrical lateral wall portion 1 formed with n multitude of closely spaced small perforations 3 distributed over its entire surface. As shown, the drum is closed at one end by an imperforate sheet metal end wall portion 5 and at its opposite end by a sheet metal end wall portion 7, theselend walls preferably being welded at their peripheries to the lateral wall. The end wall '7 is imperforate except that it is provided with a central opening 9 which receives the discharge end portion of an air blast tube ll of a conventional gun type oil burner indicated in its entirety by the reference numeral 13. The end of the blast tube preferably is somewhat loosely received by the opening 9 so as to allow for relative expansion of the parts.

The oil burner 53 is shown as comprising a casing 15 containing an electric motor driven rotary fan 17 for forcing air through the blast tube into the drum, the amount of air so forced being regulated in the usual manner by adjustable shutters (nots'nown) on the end of the casing, which shutters control the efiective crosssectional area of the air intake to the fan. t

i, As in the conventional gun type oil burner, .apump 19 adjacent the combustion chamber a spray nozzle 27 for atomizing the oil. Also, as in the usual gun type oil burner, for regulating and maintaining constant at a selected value the pressure of the oil supplied the nozzle, the pump is provided interiorly of its casing with a manually adjustable, spring pressed, automatically acting bypass valve (not shown) in a passage ,(also not shown) connecting the pump outlet to a second passage, with which latter communicates a pipe 28 for returning the excess oil passing the bypass valve to the oil tank, the adjustable means for the bypass valve being accessible from the exterior of the pump casing.

Also, as shown, positioned within the blast tube 11 is a circumferential series of stationary vanes 29 for causing a whirling action of the air discharged from the blast tube and, as further shown, interiorly of the blast tube are positioned adjacent the nozzle the usual spark electrodes 31 for igniting the mixture of atomized oil and air discharged into the combustion chamber.

lnteriorly of the drum the end wall 7 thereof is shown as carrying an imperforate sleeve 33 which is of heat refractory material, preferably sheet metal. The sleeve may be welded at one end to said end wall.- As shown, it has an open end intermediate the length of the combustion chamber facing the end wall 5.

The nozzle 27 preferably is of the common type which discharges a so-called whirling spray of atomized oil which tends to be of approximately conical shape having a wide apex angle, say from about 50 to degrees. The whirling air blast discharged from the blast tube however tends to tear this spray to pieces so as thoroughly to mix the air and atomized oil and, preferably, without oil particles impinging on the inner surface of the sleeve 33. This ignited mixture produces a flame within the sleeve, this flame contacting the interior wall surface of the sleeve from a point slightly in advance of the end wall 7 to the forward end of the sleeve or at least close to such forward end. The sleeve acts to keep the flame from contacting that portion of the perforated lateral wall of the drum which directly surrounds it. The interior surface of the sleeve which the flame contacts tends to deflect the flame toward the axial line of the combustion chamber, as schematically indicated by the arrows 35 in Fig. I, so that the flame which escapes from the open end of the sleeve is prevented from contacting that portion of the perforated lateral wall of the drum which lies between the open end of the sleeve and the end wall 5 of the drum. The flame when so deflected is of such pattern that it is of longer length along the axial line of the drum than adjacent the walls of the sleeve, and also by properly regulating the amount of oil supplied the nozzle may be made of such pattern that it does not contact the end wall 5 of the drum. The sleeve preferably is of such length that the front of the flame projects somewhat from it, say several inches. The sleeve is heated to incandescence, and the heat radiated from it and the flame and the hot products of combustion heat the walls of the drum to incandescence.

In the construction described the flame and products of combustion produced thereby create a pressure within the drum at the exterior of the sleeve 33 somewhat in excess of that of the surrounding atmosphere so that the products of combustion discharge through all of the perforations 3. Within the sleeve at points adjacent the opening 9 that receives the end of the blast tube the pressure will be less than that of the surrounding atmosphere because of the ejector action at the blast at such eral wall ofthe drum.

point. However, such lower pressure will prevent the discharge of combustion products or flame through any clearance which may exist between the blast tube and said opening 9. Any air which may be drawn through suchclearance will be in small amount and will go into the mixture and hence will produce no deleterious effect. Preferably the drum and amount of oil burned therein are such that the entire extent of its exterior walls will be heated to incandescence, and the same is true of all the other forms of drums hereinafter described.

As in applicants patent above referred to, and as pointed out by that patent, it is necessary, in order to secure complete combustion of the fuel and thus avoid the discharge of smoke and dangerous amounts of poisonous carbon monoxide from the drum, to have the closely spaced small perforations 3 in the walls of the drum constitute substantially the sole means of escape of combustion products from the drum, also to heat the perforated portions to high incandescence, and further to prevent the flame from contacting those perforated portions. In absence of the sleeve 33 or" the present invention it is somewhat difficult to secure a flame of such pattern that it will not contact the perforated lat- Without the sleeve severe restrictions areplaced on obtaining a spray from the nozzle that will properly with the combustion air discharged from the blast tube and at the same time having the mixture produce a flame of such pattern that it will not contact the lateral wall of the drum. Tbeserestrictions however are removed when the sleeve is employed. it has been found that when the sleeve is employed a proper mixture may be readily secured, and with a lesser amount of excess air for the same amount of oil than is necessary to secure a flame of desired pattern when the sleeve is not employed. Also the sleeve being heated to incandescence and the flame contacting it the sleeve acts to promote combustion of the fuel and in that way further tends to reduce the amount of excess air necessary to secure proper combustion of the fuel. Although complete combustion will be obtained whether or not the sleeve is employed, and thus the same amount of heat generated for the same amount of oil, the lesser amount of excess air necessary when the sleeve is employed results in the production of combustion products being at a higher temperature, which higher temperature may be availed of to secure a higher temperature of the drum and thus increase the amount of heat radiated from it. Such higher drum temperature it will be realized is of importance when it is observed that tl e amount of heat radiated by the drum varies with about the fourth power of the temperature difference between it and its surroundings. in practice it has been found that the amount of excess air over that stoichiometrically necessary to secure complete combustion may be reduced from about l5 percent when the sleeve is not employed to about 5 percent when the sleeve is employed, with an increase of about 12 to 16 percent in the temperature of the combustion products for the same amount of oil burned, for example, a rise in the temperature from about 1300 to l500 'Also, andirnportantly, it has beenfonnd that'when the apparatus without the sleeve is placed outdoors and subjected to the Wind, or indoors and subjected to a strong external draft, the flame may be blown into con.- tact with the perforated lateral wall of the drum with the result in such cases that a smoky discharge contain.-

ing dangerous amounts of carbon monoxide will occur through the perforations. By employing the sleeve such action of the wind or draft may be effective y prevented. To insure best results in such cases the sleeve should he'of' such length that the flame projects no'rnore than a few inches from its open end.

Further, it is desirable to have the front of the flame oflar'ge area so as to radiate heat more effectively for heating the portions: of-the perforated wallsof the drum r v I "2, 69, 26;

in advance of it. The sleeve may be of such diameter that it is relatively close to the lateral wall of the drum. The closer it is to such wall the more the sleeve, which is heated by the flame to incandescence, tends to heat that wall. The space between the sleeve and such wall need not be more than will permit the combustion gas to travel freely about the exterior of the sleeve to the perforations 3 in the portion of said well which surrounds it. Satisfactory results will be secured if such space is even as small as about inch. When the sleeve is not employed it is dilficult, if not impossible, to secure a flame of such pattern with assurance that it will not at times at least contact the perforated portion of the lateral wall of the drum surrounding it, particularly with the ever present possibility with portable apparatus that the drum will be subjected to the wind or strong drafts tending to blow the flame into such contact. When the sleeve is not employed'seldom can the flame be permitted to approach closer to the portion of the perforatedlateral wall surrounding it than 2 /2 inches. The effect of the sleeve in these respects may be readily appreciated by comparing a drum 12 inches in diameter with a sleeve permitting the flame to approach the surrounding perforated lateral wall inch with the same drum without the sleeve and the flame approaching such wall portion 2 /2 inches. In the first case the flame will be 10 /2 inches in diameter, and in the second case 7 inches in diameter. Thus employment of the sleeve in such instance more than doubles the heat radiating area of the flame front.

As in the apparatus according to the aforesaid patent, the sheet metal constituting the perforated portion of the combustion chamber preferably is of heat refractory stainless steel, and preferably is as thin as structural requirements will permit, sheet metal of about inch giving satisfactory results in most instances. This thickness, however, is not critical, but may be varied within wide limits. The sheet metal of which the sleeve 33 is made also preferably is of heat refractory stainless steel.

Also it has'been found, as in the apparatus according to said patent, that the diameter of any perforations in the combustion chamber walls permitting escape of combustion products should not exceed approximately 0.15 inch, or otherwise have a cross-sectional area greater than approximately that presented by a perforation of such diameter, namely, a cross-sectional area of approximately 0.018 square inch, as otherwise incompletely burned combustion products will escape through them usually in the form of smoke having a pronounced odor and'containin'g dangerous amounts of carbon monoxide. The perforations may have diameters as small as possible, and preferably are as small as can be economically produced, say about 0.08 inch. It has been found, however, that the number of perforations and their sizes maybe varied so long as the total area presented by the perforat1ons per square inch of perforated surface is approximately from 0.05 to 0.14 square inch.

It has been further found if the sleeve 33 is not employed that, as pointed out in said patent, to secure complete combustion the cubic contents'of the combustion chamber should be approximately from 2369 to 4000 cubic inches per gallon of oil burned per hour, with'the total perforated surface, that is to say, the total area of the perforations and the intervening metal, expressed 1n square inches, from about 15 to 35 percent of the arithmetical value of the cubic contents of the combustion chamber expressed in cubic'inches. When the sleeve is employed it has been found, however, that these permissible ranges are broadened, the range of 2390 to 4000 cubic inches being broadened to about 2000 to 45%}0 cubic inches, and the range of 15 to 35 percent being broadened to about 13 to 40 percent, in which respect it will be observed that'these'broader ranges include narrower ranges specified. r

The -kind of-oil burnedin "tbe 'improved apparatus actory results having been secured with ordinary commercial gasoline, kerosene, and all grades of commercial fuel up to so-called No. 3 fuel oil. Preferably, however, socalled No. 2 fuel oil is employed.

The perforated portion of the combustion chamber in most cases preferably is confined to the cylindrical or other lateral wall of the drum. The end wall 5 of the drum may, if desired, be perforated as shown at 37 in Fig. 2, so as to constitute part of the perforated portion of the drum. Such perforations may extend over the en- 'tire surface of the end wall or be confined to part of such surface. When perforated this end wall should be positioned far enough from the adjacent end of the sleeve 33 to prevent the flame from contacting such wall. Because the total area presented by the perforations when both the lateral Wall and end wall 5 are perforated is the -sumof those presented by each wall, the drum in such case may, within limits, be made shorter than if the lateral wall only were perforated and the same amount of oil is being burned, with the result that there is less metal presented by those walls to be heated and consequently if the same amount of oil is burned such walls will be at a higher temperature, which may be desirable when a concentrated area of high radiating capacity is wanted.

The relation between the diameter of the drum and its length is by no means critical, satisfactory results being secured when the length of the drum is from 100 to 400 times its diameter. When a cylindrical drum is employed, and its entire lateral surface is perforated, the relation between the diameter of the drum and its length is by no means critical, satisfactory results having been secured when the length of the drum is from 100 to 400 percent of its diameter. Examples of having their lengths Within such range are drums 12 inches in diameter and 19 inches long, 15 inches in diameter and 18 inches long, 22 inches in diameter and 24 inches long, 22 inches in diameter and 36 inches long, and 26 inches in diameter and 30 inches long, with the diameter of the sleeve 33 being about 80 percent of the diameter of the drum, and with the length of the sleeve slightly less than its diameter. Other proportions between the length and. diameter of the drum, however, may be employed. Satisfactory results have been secured with drums the lengths of which are less than their diameters,'for example, with a drum 22 inches in diameter and 18 inches long and with the diameter of the sleeve 33 about 80 percent of the diameter of the drum and the length of the sleeve slightly less than about half the length of the drum, in which particular instance the length of the drum is but aboutSO percent of its diameter.

Whether or not the end wall 5 of the drum is perforated,

the perforated portion of the lateral wall of the drum need not extend the entire length of such wall. For example, as shown in Fig. 3, the drum may have a lateral wall portion 39 which is perforated throughout its extent and an imperforate portion 41 making up the remainder ,ofits length, this imperforate portion being secured at one end to the adjacent end of the perforated portion and at its opposite end to the end wall 7 of the drum, 1n

each case preferably by welding. a

. When the imperforate portion 41 of Fig. 3 is long enough, say approximately the length of the sleeve 33 of that figure, said sleeve may be omitted to produce the combustion chamber according to Fig. 6 in which the lateral wall of the drum comprises the imperforate portion 43 adjacent the end wall 7 and the connected portion 45 which is perforated, throughout its entire extent, the

construction being otherwise the same as that of Fig. 3. In the construction shown by Fig. 6 the inner surface of the imperforate portion 43 will tend, like the inner surface of the sleeve 33 of Fig. 1, to deflect the flame contacting it toward the axial line of the drum as schemati- 'cally indicated by the arrows 46 of Fig. 6, in other Words,

, tion according to Fig. 6, the parts will be so designed that the flame will cease to contact the inner surface of the imperforate portion 43 at points slightly to the rear of the forward end of said portion so as better to insure against the flame contacting the perforated portion of the lateral wall. The front of the flame adjacent the axial line of the drum may project beyond the imperforate portion of the drum so long as it does not contact the perforated portions of the end wall 5 of the drum if that end wall has perforations. However, preferably it should not project more than several inches if the imperforate portion 43 is to act like the sleeve 33 of Fig. 1 in protecting the flame against the action of the wind or strong external drafts.

Further, the perforations of the lateral wall of the drum may be arranged in bands with imperforate bands between them for spacing them, as shown in Fig. 4. The

' drum according to Fig. 4 comprises the sleeves 47 perforated throughout their entire extent and separated by imperforate sleeves 49, the perforated sleeve 47 adjacent the end wall 5 if desired being spaced from and connected to that end wall by the imperforate sleeve 51,

and the perforated sleeve 47 adjacent the end wall 7 if desired being spaced from and connected to that endwall by the imperforate sleeve 53. As shown, all these sleeves abut and preferably are secured together by welding.

The sleeves 33 of Figs. 1, 3 and 4 need not be cylindrical, but may be conical as shown at 55 in Fig. 5, this conical sleeve being contacted by the flame and tending to deflect it toward the axial line of the drum, as schematically indicated by the arrows 56. In Fig. 5 the lateral wall of the drum is like that shown in Fig. 1, but if desired may be like those shown in Figs. 3 and 4.

Theinterior surface which surrounds and deflects the flame for preventing it from contacting the perforated lateral wall portion of the drum may be positioned exteriorly of the main portion of the drum, as shown in Figs. 7 and 8. In these figures the main portion of the drum may comprise the perforated cylindrical portion 1 identical with that of the drum according to Fig. l, or may comprise the lateral wall 39, 41 of Fig. 3, or the lateral wall 47, 49, 51, 53 of Fig. 4, in each instance the end wall 5 of the drum being perforated if desired.

In Fig. 7 the end wall of the drum opposite the end wall 5 thereof is in effect made in two sections, the annular section 57 having the central opening 59 and the section 61 having the opening 9 for receiving the end of the blast tube Ill, these two sections being connected by an imperforate sleeve 63 of smaller diameter than the perforated portion 1 of the drum, which sleeve at one end registers with the opening 59 and at its opposite end is closed by the section 61. The interior wall surface of the sleeve 63 will surround and tend to deflect the flame in the same way as the corresponding surface of the sleeve 33 of Fig. 1 so as to keep the flame from contacting the perforated lateral wall portion of the drum.

As shown in Fig. 8, that end wall of the drum which is opposite the end wall 5 is generally of frusto-conical shape. As shown, it has the actual frusto-conical portion 65 which at its larger end is connected by a narrow cylindrical band-like portion 67 to an outwardly projecting annular flange 69 secured, as by welding, to the adjacent end of the perforated lateral wall portion of the drum. The smaller end of the frusto-conical portion65 receives the discharge end of the blast tube 11. The interior sur' faces of the frusto-conical portion 65 and cylindrical portion 67 of the end wall will surround and tend to deflect the flame into the space surrounded by the perforated portion 1 of the drum in such way as to prevent the flame from contacting. such perforateduportion, the cylindrical portion 67 being of diameter less than that of the perfo- Fig. l is perforated over its entire extent, the imperforate portions of the drums of Figs. 3, 4 and 6 necessarily must make those drums longer than the drum of Fig. .1. The cubic contents of these longer drumswill be greater than the cubic contents of the drum of Fig. l, but the same amount of oil may be burned in them with the same amount of combustion air as in the drum of Figfl provided that, as above explained in each case such oil is burned at the rate of one gallon per hour for approximately, each 2000 to 4500 cubic inches of the cubic contents of the drum with the total perforated surface being from about 13 to 40 percent of the arithmetical value of such cubic contents expressed in cubic inches, and all parts of such total perforated surface are heated to incandescencc. The heat generated by the burning of the oil and the temperature of the combustion products in the drum will be the same in each case, but in the longer drums because there is more metal to be heated by those combustion products the walls of such longer drums will be heated to a lower temperature than the walls of the shorter drum. This securing of walls of greater area and lower temperature while burning the same amount of oil may be desirable when a large surface area of the drum is wanted to secure a wider distribution of the radiant heat under conditions where ahigher temperature of the incandescent walls is unnecessary.

Also it will be observed that the drum of Fig. 7 is lengthened and its superficial area and cubic contents increased, as compared to the drum of Fig. l, by the sleeve 63 of the drum of Fig, 7, if the lateral wall 1 and end wall of'the drum of Fig. 7 are identical in all respects with the lateral wall 1 and end wall 5 of the drum of Fig. 1. Likewise it will be observed that under the same conditions the generally frusto-conical end wall of the drum of Fig. 8 increases the length and superficial area and cubic contents ofthat drum over those of the drum of Fig. 1. The drums of Figs. 7 and 8 therefore present constructions which may be availed of to secure the same results as those above explained in connection with the drums according to Figs. 3, 4 and 6.

Another way of increasing the superficial area and cubic contents of the drum, while maintaining the same amount of perforated area of the lateral wall of the drum, as inw dicated by Fig. 9 which shows a fragment of a development of the surface of a metal sheet from which the lateral wall of the drum may be formed. As shown, the perforations 3 of this sheet are confined to a plurality of spaces 71 which are separated in both horizontal and vertical directions as viewed in Fig. 9. Therefore such sheet may be employed as a substitute for the sheet forming the lateral wall of the drum of Fig. l for increasing either or both the lengthand diameter of the drum while preserving the sam'eamount of perforated area of said lateralwall, 7'

In all these cases of drums having lateral walls which comprise perforate and imperforate portions the sleeves 33 of Figs. 3, 4 and 6, the sleeve 63 of Fig. 7, and the generally frusto-uonical end wall of Fig. 8, as the case may be, surrounding and deflecting the flame, act effectively to prevent contact of the flame with the associated perforated area or areas of the lateral wall of the drum without putting any restrictions on the amount of combustion air necessary to produce a flame of such pattern as will prevent such contact and thus enable the amount of excess air to be reduced to a minimum. 7

-It will be understood. that within the scope of the appended claims wide deviations may be made from the forms of the invention described without departing from the spirit of the invention.

I claim:

1. Oil burning apparatus having a drum-like cornbus tion chamber comprising opposite end walls and a lateral wall of thin heat refractory metal, at least the lateral wall of the wall portions constituted by such wall and one end wall being formed with a multitude of small perforations, each having a transverse cross-sectional area not exceeding approximately 0.018 square inch which are so spaced as to present approximately from 0.05 to 0.14 square inch of total transverse cross-sectional area per square inch of perforated surface, constituting substantially the sole means for discharge of combustion products from said chamber, and an air blast tube and an associated oil atomizing nozzle and ignition means for discharging into said chamber through its opposite end wall toward its other end wall an ignited mixture of atomized oiland air for producing therein a flame at the end of said chamoer adjacent said nozzle for heating the perforated wall portions to incandescence, the air of said mixture constituting substantially the only air admitted to said chamher, the chamber at its end adjacent the nozzle having imperforate means for receiving said ignited mixture and discharging flame therebeyond toward a part of said chamber having such perforations in its said lateral wall, the last mentioned means presenting an interior surface so shaped and positioned as laterally to surround the flame and be contacted and heated, to incandescence'thereby and deflect the flame inwardly toward the axial line of said chamber to cause flame discharged from such means to be of such pattern that it is continuously in out ofcontacting relation with said lateral wall and the end wall of said chamber opposite said nozzle, the flame pattern that would be produced in absence of said last mentioned means being such that the flame would contact a. perforated portion of said lateral wall.

2 Oil burning apparatus comprising a generally cylindrical combustion chamber having opposite end. walls and a lateral wall formed of thin heat refractory sheet metal, at least the lateral wall of the wall portions constituted by such wall and one end well being formed with a multitude of small perforations, each having a transverse cross-sectional area not exceeding approximately 0.018 square inch which are so spaced as topresent approximately from 0.05 to 0.14 square inch of total transverse cross-sectional area per square inch of perforated surface, constituting substantially the sole means for discharge of combustion products from said chamber, the perforations of said lateral wall extending substantially throughout its extent, the opposite end wall having an opening, means for discharging into said chamber through said opening an ignited mixture of atomized oil and air for producing a flame within said chamber at its end adjacent such end wall for heating the perforated wall portions to incandescence, said means being substantially the sole means for entering air into said chamber, and an imperforate sleeve positioned interiorly of said chamber in laterally spaced relation to said lateral wall andic'arried at one end portion thereof by the end wall having said opening and extending part way of the length ofsaid chamber with its opposite and open end facing the opposite end wall of said chamber for surrounding said flame and to be contacted and heated to incandescence thereby and deflecting the flame inwardly toward the axial line of said chamber for causing flame issuing through the open end of said sleeve to be of such pattern that it is continuously in out-of-contacting relation with said lateral wall and such opposite end wall, the flame pattern that wouldbe produced in absence of said sleeve being such that the flame would contact said lateral wall.

3. Oil burning apparatus according to claim linwhich the interior surface for surrounding and. deflectingthe flame is constituted by the interior surface of a's leev'e positioned within the combustion chamber in laterally spaced relation to its lateral wall and extending part way of its length from adjacent that end wall of the chamber through which the mixture is discharged into the chamber, the sleeve having an open end facing the opposite end wall of the chamber, and the portion of said lateral wall surrounding said sleeve having a multitude of closely spaced small perforations.

4. Oil burning apparatus according to claim 1 in which the interior surface forsurrounding and deflecting the flame is constituted by the interior surface of a frustoconical sleeve positioned within the combustion chamber in laterally spaced relation to its lateral wall and extending part way of its length from adjacent that end wall of the chamber through which the mixture is discharged into the chamber and with its open larger end facing the opposite end wall of the chamber, and the portion of said lateral wall surrounding said sleeve having a multitude of closely spaced small perforations.

5. Oil burning apparatus according to claim 1 in which the interior surface for surrounding and deflecting the flame is constituted by an imperforate portion of the lateral wall of the combustion chamber extending part way of its length from adjacent that end wall of the chamber through which the mixture is discharged into the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,943,053 Boisset Jan. 9, 1934 2,200,278 Johnston May 14, 1940 2,560,207 Berggren et a1. July 10, 1951 2,669,297 Sherman Feb. 16, 1954 

